Alert Escalation not sending alert emails more then once

Hello,

        i have configured and alert to check for HDD space. When the volume percent used is greater then 95% it sends and email.  This part works correctly, but i never get any additional emails from the Alert Escalation.

I have Alert Escalation setup to "execute this option repeatedly every 5 hours"

but i never get any emails besides the first one.

under the general tab i have check this alert every "4 hours"

i would appreciate any help with getting alert escalations to work

thanks